Grinding wheel dressing



oci. 13, 1942.

Filed March 13, 1941 F. P. HEGEMAN @BINDING WHEEL DRESSING 4 sheets-sheet -1 FIQL MSA TTU/P/v Y.

Oct. 13, 1942. 4F. P. HEGEMAN 2,298,752

i V GRINDING WHEEL DRESSING Filed Marohl. 1941 4 Sheets-Sheet 2 Oct. 13, 1942. F. P. HEGEMAN 2,298,762

GRINDING WHEEL` DRESSING Filed March 13. 1941 4 Sheets-Sheet 3 0er.' 13.*, 1942. F, P, HEGEMAN 2,298,762

GRINDING WHEEL DRES S ING Filed March 13, 1941 4 Sheets-Sheet 4 4Me /yf/SZTTUR/vfx Patented Oct. 13, 1942 2,298,762 GRINDING WHEEL DRESSING Franklyn P. Hegeman, Union, N. J., assgnor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application March is, 1941, serial? No. 383,197 16 claims. (ci. 12s- 11) This invention relates to grinding wheel dressing and associated mechanism. An object of the invention is to provide improved mechanism for dressing the surface of a reciprocating grinding wheel. Another object is to provide improved wheel dressing mechanism wherein a dressing tool is fed towards the grinding wheel with increasing increments so that compensation will be obtained'for the more rapid wear on the wheel as its diameter decreases in use. Another object is to provide means to control actuation of the dressing tool by the advance and retreat of a main slide on which the grinding wheel is constantly reciprocated. n

To these ends and also to improve generally upon devices of this character, the invention consists in the Various matters hereinafter described and claimed. In its broader aspects, the invention is not necessarily limited to the specie construction selected for illustrative purposes in the accompanying drawings in which Fig. 1 is a front elevation with some parts in vertical section and with details of the work head and wheel dresser omitted.

Fig. 2 is a plan view, with some parts in sec-V tion, of the wheel head and associated slides.

Fig. 3 is a right hand end view of Fig. 1 with some parts in section.

Fig. 4 is a cross sectional View of the two uppermost slides, some of the wheel head appearing in elevation.

Fig. 5 is a plan view of the wheel dressing mechanism.

Fig. 6 is a front view of Fig. 5, the hand wheel being removed.

Fig. 'lis an end view of the compensating mechanism. I

Fig. 8 is an end view of the guide for the dresser slide.

Fig. 9 is a perspective view of details of the ratchet mechanism.

Fig. 10 is a perspective view of a portion of the cover for the slideway.

Referring to Figs. 1, 2 and 3, the machine comprises a main frame I0 on which is slidably mounted a lower or main slide I2 which is given one reciprocation 'at each cycle of grinding substantially asin Van Norman Patent 2,149,409. The left end of the machine may'carry an oscillating head when grinding curved work or, by means of an adapter, the head can be xed in an angularly adjusted position so that tapered work or straight cylindrical work may be ground. The machine will be described with special ref- `the right end of the frame there are at and the grinding operation.

A cross slide I4 sliding on Ways I5 is adapted to be fed by a feed screw I8 which is actuated by ratchet mechanism similar tothat of the patent. The cross slide has ways near its front to support an upper or grinding wheel slide 20 which is narrow and light and continuously reciprocated through a short stroke, the slide also supporting dressing mechanism which also normally partakes of the reciprocating movement. As appears best in Fig. 4, to guide the slide 20, a front slideway or guide bar 22 is fastened to the cross slide I4 by boltsr while a rear slideway or gib 24 is adjustably secured to the crossslide by bolts 26 passing through slots in the bar. The ways are V-shaped and a take-up is provided by screws `28 threaded in a lug on the 'cross slide and locked by a brass shoe which is backed up by a set screw. Oil conduits to conduct oil to the ways are provided and the ways are covered at the front by a dust shield 30 having an end ange which covers the end of the slideway. A similar dust shield 32 covers the rear slideway. The upper'slide 23 has at one end an upright portion or head 34 which is split at 36 and adapted to clamp a split eccentric bushing 38 in which the grinding spindle quill 4l! is mounted, the bushing 38 being removable to permit the mounting in the head of a larger size quill. The

` grinding wheel 42 has its spindle mounted for rotation in this quill and it is driven by a pulley 43 and a belt from a pulley not shown on a motor adjustably mounted upon ways 43 on the top, rear portion of the cross slide I4.

Referringparticularly to Figs. 1, 2 and 3, the mechanism for giving continuous reciprocation to the upper slide 20 comprises a pair of lugs 48 projecting downwardly from the slide through a slot inthe cross slide I4, the lugs supporting a pivot pin 50 on which aremounted a pair of tapered roller bearings 52 whose outer race rings are separated by a spacer. The inner race rings of the bearing are held on the pin 50 by a nut. The outer race rings are contained in an enlargement 54 of a link 56, the bearings being covered by cover plates 58. The other end of` the link also has a similar enlargement 60 closed by cover platesas indicated best in Fig. 3. In the enlargeerence to the grinding of tapered raceways. At 55 mentare similar tapered bearings 62whose inner race rings are clamped upon a crank pin 64 projecting from a slide 66 adapted for movementl of adjustment in ways formed across an enlargement 68 of a driven shaft 10. The slide 66 is adjustable to vary the throw of the crank pin 64 by means of an adjusting screw 12 threaded therein and held from endwise movement by a plate attached to the enlargement 68..

The shaft 10 is yjournalled for rotation in tapered roller bearings 14 contained in a housing 16 on a bracket 18 which is bolted to the cross slide I4. The bearings are covered by suitable caps containing seals. The shaft 10i's driven' by a pulley 80 connected by a belt to a pulley 82 on an electric motor 84 which is fastenedona pivoted supporting plate 86. The plate has a boss 88 with a hinge pin which projects into rubber bushings carried by lugs 90V upon anupright bracket which is bolted on the cross slide YI-4 near the rear. The boss 88 has a downwardly extending arm 92 4provided-withuan abutment screw '94 which' is adjustable to,-va'r-y.y the `position of the motor and. tightentheffbelt.

Referring particularly toFig.V 4, the upright portioni'of" the uppenslidel 20L hasa key' 96' to' locate a guide or housing98'lwhich is 'bolted on the upright part and hasna cover tol form a rectangular guide fora slide |02 which-pertainsto the dressingl of the grindingrwheel. A gib. plate|04 bears'against the upper side of the slide and is` backed upiby cap:v screws. Where the slide projects through: the en'dso'f the housing, tight Vjoints arelformed by caps |06havi'ng` rectangular openingsfandprovided with packings.' `As shown-'best inFig; 5, one'end offtheslide |02y is fastenedv bys'crews ina grooverextending at an' angle across th'eitopofv a bracket ornut |08* which is Vslit underneath arid'internally threaded to receive a feedfscrew I| 0 havinga nib I |2'which` carries a dressing' diamond ||4v atthe end: A ratchet wheel |165 is keyed'toa reduced" portion of the feed screw I|0and` hasea projecting hub I I8 on which' a pawl supporting arm |20 is looselyY mounted for pivotal movement. The arm has a pivot stud |22 to pivotally mounta pawl |24 which is urged towards the ratchet wheel by a leaf spring |126. The pawl-'basa lifting pin` |281 projecting laterally over the arm I20`.` The arm has extensions |30 adapted to abut; lin Various posi-y tions ofv advance, against a stopscrewA |32 adjustably fastened to a lug |'33-'onA the-cover |00, the' arm being urged towards the stop-screwby a' coil spring |34, connected to a pirr |36v on thearm |20 and to the bent end-ofv anY anchor pin |38" The'screw" |32'can -bemanually turned for adjustment by' fastenedto the bracket or nut |08.l

a knurled head |40 but the cross feed of'the diamond is automatic and occurs whenever the slide |02 is'retracted.

When the main slide-I2 retreats, as at'the' end of a cycle, the slide |02 and the dressing mechanism are advanced, as will appear, carrying thev pawl supporting arm |20- away from the stopr Thus, during advance of theslide |02 andY more or less into the lug |33 and clamping it with a screw. The tapered cam or stop plate |48 and the pin |44 provide means to automatically increase the advance of the diamond to compensate for increasing wear on the wheel as the latter decreases in diameter, it being evident that the feed screw ||0 intermittently moves the ratchet mechanism towards the wheel and so advances the pin |44 along the tapered cam plate The following mechanism (best shown in Fig. 1) causes the advance of the slide |02 at the end of each grinding cycle. A clevis |50, fastened to the rear end of the slide |02, is pivotally connected to one. end of an actuating rod or link |52;l the other end` of the actuating rod being pivotally connected to the upper end. of an actuating lever |54 which is in the form of a bell crank. The lever is pivotally mounted on a headed pivot stud |56 threaded in a lug upon a bracket |58 which is fastened to the upper slide 20. The shortarm ofthe bell crank' carries a roller |58 adapted to ride along the enlarged rectangular head of a plunger |62 which is vertically slidable in bushings in a housing |64 which is fastened on they main or lower slide I2.

The upper bushing is held from rotationby a dowel pin A|66 projecting into' a slot of thehou'sing |645 and the plungeris held from rotationv in the'bushing by a keyfpin projecting intoa keyway. The lower end of the plunger carries-a cam roll |68 adapted to ride on an inclined cam |10 fastened in a grooveof a cam bracket |12 which is` fastened on the main frame. Whenthe main slide is retracted to withdraw the grinding wheel from the work, the rollerruns up thev cam, lifting abutment sleeve engages a nut ITB-threaded on the rod' and the other engages a rounded surface on the lever |54, the rod |16V passing through a diverging slot in the lever and havingfa stopVV nut I 18 fastened thereon and engaging a' rounded surface on theother side of'the lever.Y The rod |16-is threaded in a sleeve |80 which is:flat' at the sides to fit between ears on a forked stud |82 fastened-to the housingl 98 and having a pivot pin for the sleeve |80. The coil springr|14 will arm |20 against the stop screw |32. 'Ihisoccurs whenever the main slide advances'and` re"-4 connected by a rod 236 and a coupling .238"to.

the main slide, the cam actuating a vertical plunger 240 in the axis of an oscillatable. column 244. The plunger slides in a bushing' in' a plate 248 attached to a workA head base' 248 which is.

fastened on a swivel base 250. When grinding straight or tapered work; the swivelv base is bolted to an adapter 216 which has a circular-groove 218 of T-shaped section to receive headed nuts 280 which are threaded on clamping bolts 282 passed up through a ange on the frame. The work head is thus capable of angular adjustment but it can be oscillated for use with curved work.

I claim:

l. In apparatus. of the character indicated, a wheel slide having a grinding Wheel, means for constantly reciprocating the wheel slide, a housing mounted on the wheel slide, a dressing slide shiftable in the housing but normally reciprocating with the wheel slide, a dressing toolr on the dressing slide, a plunger, and a cam engaging the plunger for shifting the dressing slide with respect to the wheel slide to thereby traverse the dressing tool along the grinding wheel.

2. In apparatus of the character indicated, a main slide adapted for advancing, and retreating movement, a wheel slide mounted on the main slide for reciprocation in the direction of said advancing and retreating movement and having a grinding wheel, means for constantly reciprocating the wheel slide with respect to the main slide, a dressing slide on thewheel slide and normally reciprocating therewith, a dressing tool on the dressing slide, and means for shifting the dressing slide with respect to the constantly reciprocating wheel slide to thereby traverse the dressing tool along the grinding wheel.

3. In apparatus of the character indicated, a main slide adapted for advancing and retreating movement, a wheel slide mounted on the main slide for independent reciprocation with respect to the latter and having a grinding wheel, means for constantly reciprocating the Wheel slide with respect to the main' slide, a dressing slide on the wheel slide and normally reciprocating therewith, a dressing tool on the dressing slide, and means responsive to a shifting movement of the main slide for causing the dressing slide to shift with respect to the constantly reciprocating Wheel slide and thereby traverse the dressing tool along the grinding Wheel.

4. In apparatus of the character indicated, a main slide adapted for advancing and retreating movement, a wheel slide mounted on the main slide and having a grinding wheel, means for reciprocating the wheel slide with respect to the main slide, a dressing slide on the wheel slide and normally reciprocating therewith, a dressing tool on the dressing slide, a plunger shiftable on the main slide, actuating means between the plunger and the dressing slide, and a relatively xed cam for controlling shifting movement of the plunger in response to movement of the main slide.

5. In apparatus of the character indicated, a main slide adapted for advancing and retreating movement, a wheel slide mounted on the main slide and having a grinding wheel, means for reciprocating the wheel slide with respect to the main slide, a dressing slide on the wheel slide and normally reciprocating therewith, a dressing tool on the dressing slide, a plunger shiftable on the main slide, a pivoted lever having one arm riding on the plunger, actuating connections between the other arm of the lever and the dressing slide, and a Xed cam controlling the plunger.

6. In'apparatus of the character indicated, a main slide adapted for advancing and retreating movement, a wheel slide mounted on the main slide and having a grinding wheel, means for reciprocating the wheel slide with respect to the main slide, a dressing slider on the wheell slide and normally reciprocating therewith, a dressing tool .on the dressing slide, a plunger shiftable on the main slide, a lever pivotally mounted on thewheel slide and reciprocable therewith, a rod connecting one arm of the lever to the dressing slide, the other arm of the lever riding on one end ofthe plunger, a spring urging said other arm against the plunger, and a cam at the other end of the plunger.

7; In apparatus of the character indicated, a main slide adapted for advancing and retreating movement, a wheel slide having a grinding wheel, means for reciprocating the wheel slide with respect to the main slide, a dressing slide on the wheel slide and normally reciprocating therewith, a dressing tool on the dressing slide, a plunger shiftable on the main slide, a cam to shift the plunger in response to movement of the maink slide, means operably connected to the dresser slide and having a member in bearing engagement with the plunger, and one of the engaging parts being elongated to maintain contact with the other as the wheel slide shifts with respect "to the `main slide andthe plunger,

8. In apparatus of the character indicated, a mainrslide adapted for advancing and retreating movement, a feed slide movable crosswise of the main slide, a wheel slide guided parallel to the main slide by the cross slide and having a grinding wheel, means for reciprocating the wheel slide, a dressing slide on the wheel slide, a dressing tool on the dressing slide, a plunger shiftable on the main slide, a xed cam to shift the plunger in response to movement of the main slide, means connected to the dresser slide and having a member in bearing engagement with the plunger for transmitting movement of the plunger to the dressing slide, and said plunger having an enlarged head to maintain contact with the member as the cross slide and the Wheel slide shift with respect to the main slide.

9. In apparatus of the character indicated, a Wheel slide having a grinding Wheel, means for reciprocating the wheel slide, a dressing slide mounted on the wheel slide and normally reciprocating therewith, a dressing tool having a feed screw supported by the dressing slide, means for shifting the dressing slide to cause the dressing tool to traverse the grinding wheel, and means for causing said shifting movement of the dressing slide to effect a turning of the feed screw.

10. In apparatus of the character indicated, a wheel head having a grinding wheel, a dressing slide shiftable with respect to the wheel head, a dressing tool mounted for feeding movement towards the grinding wheel, means for reciprocoting the dressing slide to traverse the dressing tool along the grinding wheel, and means for causing one of the reciprocating strokes to feed said dressing tool towards the grinding wheel.

11. In apparatus of the character indicated, a wheel head having a grinding wheel, a dressing slide shiftable with respect to the wheel head, a dressing tool having a feed screw carried by the dressing slide, means for shifting the dressing slide to traverse the dressing tool along the grinding wheel, and means for causing said shifting movement to effect a turning of the feed screw.

12. I n apparatus of the character indicated, a wheel head having a grinding wheel, a dressing slide shiftable with respect to the wheel head, a

dressing Atoolhavinga feed .screw .carried by :the dressing slide, means. :for-.shifting the 1 dressing slide to traverse the. dressing tool :alongxtl'ie grinding wheel, means for causing. said ,'shiftin'gfmovement to effect a' turningmovement offthe feed t screw, and means for causingisaid turningrmovement to increase in amplitude'lwhen,repeated.

13.- In apparatus of the characterzindicated; a

'wheel head having a grindingfwheeLal dressing slide shiftable with respect to thewhe'el head, al `dressing tool having .a feed screw carried byithe dressing slide, means for shiftingfftheldressing slide to traverse the dressing'tool along'thegrinding wheel, and ratchet mechanism'energized by said shifting movement' for turning theifeed screw.

14. In apparatus of the characterindicatedg a wheel head having a'grinding wheel, adressing slide shiftable with respect to the 'whee1:head, a

dressing tool having a feed screwcarried bythe;V dressing slide, a ratchet Wheel on the feed screw, -a feed pawl, a movable arm carrying the-pawl, an 'abutment member on the wh'eel'head,l aspring for urging the arm towards theabutmentmember, and means for shifting thel dressing slide;

with respect to the abutment member to-cause the dressing tool to traverse Vthe grinding -Wheel and'to effect an' actuationof the feedfpawl.

15; In apparatus of the character indicated, a

wheel head' having: av 'grinding wheel,A a. dressing `slide.shiftable-with respect to the wheelhead, a 4dressing tool mounted for feeding movement towards the, grinding wheel, a member having an idle movement` in one direction and a working movement in the other direction to effect a feed of the dressing tool, means for reciprocating the .dressing lslide to oscillate the member, and a tapered cam for controlling increase in the amplitude of successive oscillations of the member.

v16..2In' apparatus of the character indicated, al wheel head having a grinding wheel, a dressing slide vshiftable with respect to the wheel head, a .feed nut carried bytheslide, a dressing tool hav- -ing a feed screw threaded in the nut, a ratchet wheel von the feed screw, a feed pawl, a movable Aarm carrying the pawl, an abutment member on the wheel head', a spring for urging the arm in a idirection towards the abutment member, means FRANKLYN P. HEGEMAN. 

